• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.10 no.6
• /
• pp.130-138
• /
• 2007

To protect the surface of ground-cutting slopes occurring at the national road substitute detour [roundabout road]construction jobsite between Munduk and Wubokgu within the jurisdiction of Pohang-si and environment-friendly road construction, a test execution of re-vegetation measures on the major slopes was done and the results are as follows : As a result of finding out the number of sprouting individuals on the test construction site, the average number of sprouting individuals on the three test spots by the method of revegetation measures D, revegetation measures A, and revegetation measures B was 1,292 number of per square meter, 1,190 number of per square meter, and 1,095 number of per square meter respectively, which statistics were higher than those of test spot by the revegetation measures C. As a result of finding out living plant's breeding index [weight in dried state], the average dried weight of living plant at the test spot by the method of revegetation measures B, in case of foreign herbal species, was the highest marking 8.96 grams per square meter, and the next was 6.86grams per square meter by the method of revegetation measures D, and the next after was 6.80 grams per square meter by the method of revegetation measures A, and the last 5.93 grams per square meter by the method of revegetation measures C. As a result of finding out the covering degree on the slopes, the same average covering degree of 80% and 77.5% in revegetation measures A and revegetation measures D individually, which showed a somewhat higher covering degree than those of revegetation measures B and revegetation measures C. As a result of finding out appearing plants on the test construction site, seeding plant life was found to be sprouting on all test spot while native and foreign herbal species and herbaceous plant as well as shrubs were growing in good harmony with each other. However, in case of revegetation measures B and revegetation measures C method, foreign plant species are dominantly growing. As a result of inspecting rifts on the slopes and the excavated state by water, there existed cracks in some of base materials only in revegetation measures C method applied spot.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.6 no.6
• /
• pp.49-55
• /
• 2003

Total phosphorous removal rate was examined of a subsurface-flow treatment wetland system which was constructed on floodplain in the down reach of the Kwangju Stream in Korea from May to June 2001. Its dimensions were 29 meter in length, 9 meter in width and 0.65 meter in depth. A bottom layer of 45 cm in depth was filled with crushed granite with about 15~30 mm in diameter and a middle layer of 10 cm in depth had pea pebbles with about 10 mm in diameter. An upper layer of 5 cm in depth contained course sand. Reeds(Phragmites australis) were transplanted on the surface of the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream flowed from a submerged dam into it via a pipe by gravity flow and treated effluent was funneled back into the Stream. The number of reed stems increased from 80 stems/$m^2$ in July 2001 to 136 stems/$m^2$ in September 2001. The hight of stems was 44.2 cm in July 2001 and 75.3 cm in September 2001. The establishment of reeds at early operating stage of the system was good. Volume and water quality of inflow and outflow were investigated from July 2001 through December 2001. The average inflow was 40 $m^3$/day and hydraulic detention time was about 1.5 days. The concentration of total phosphorous n influent and effluent was 0.83 and 0.33 mg/L, respectively. The removal rate of total phosphorous averaged about 60%. The removal efficiency was slightly higher, compared with that of subsurface-flow wetlands operating in North America, whose retention rate of total phosphorous was reported to be about 56%. The good abatement rate could be attributed to sedimentation of particle phosphorous in pores of the media and adsorption of phosphorous to the biofilm developed on the surface of them. Increase of standing density of reeds within a few years will develop root zones which may lead to increment in the phosphorous retention rate.

• Korean Journal of Environmental Agriculture
• /
• v.22 no.4
• /
• pp.251-254
• /
• 2003

Phosphorous removal rate and emergent plant growth were examined of a surface-flow constructed treatment wetland system, whose dimensions were 31 meter in length and 12 meter in width. The system was established on floodplain in the down reach of the Kwangju Stream in Korea in one and half months from May to June 2001. Cattails(Typha angustiflora) were transplanted in the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream were funneled into it via a pipe by gravity flow and its effluent were discharged back into it. The stems of cattails grew from 45.2 cm in July 2001 up to 186 cm in September 2001 and the number of cattail stems per square meter increased from 22 in July 2001 to 53 in September 2001. The early establishment of cattails was good. Volume and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow averaged $40\;m^3/day$ and hydraulic retention time was about 1.5 days. The concentration of total phosphorous in influent and effluent was 0.85 mg/L, 0.41 mg/L, respectively. The average removal rate of total phosphorous in the system was about 52%. The retention efficiency was slightly lower, compared with that in surface-flow wetlands operating in North America, whose retention efficiency was reported to be about 57%. The lower abatement rate could result from the initial stage of the system and inclusion of two cold months into the six-month monitoring period. Root rhizosphere in wetland soils and litter-soil layers on bottoms were not properly developed. Increase of standing density of cattails within a few years will establish both root zones and substrates beneficial to the removal of phosphorous, which may lead to increase of the phosphorous retention rate. The system was submerged one time by heavy storm during the monitoring period. The inundation, however, scarcely disturb its environment.

• International journal of advanced smart convergence
• /
• v.8 no.2
• /
• pp.218-226
• /
• 2019

The use of Information and Communication Technologies (ICT) is the key to operate a change from the traditional manual reading of water meters and sensors to an automated system where high frequency data is remotely collected and analyzed in real time, one of the main components of a Smart Water Grid. The recent boom of ICT offers a wide range of both wired and wireless technologies to achieve this objective. We review and present in this article the most widely recognized technologies and protocols along with their respective advantages, drawbacks and applicability range which can be Home Area Network (HAN), Building Area Network (BAN) or Local/Neighborhood Area Network (LAN/NAN). We also present our findings and we give recommendations on the application of ICT in Smart Water Grids and future work needed.

• Fire Science and Engineering
• /
• v.29 no.3
• /
• pp.43-47
• /
• 2015

Water mist was sprayed on small compartment areas filled with smoke that formed from two different combustibles. The water-mist injection pressure and time were varied, and changes in the light extinction coefficient were measured over time. The smoke removal effect was analyzed with a light sensing smoke meter in different experimental conditions. Using the meter, the changes in smoke density were converted to changes in DC voltage over time to obtain the changes in the light extinction coefficient. The water mist was more effective in eliminating the smoke formed from glowing compared to flaming combustion. The smoke removal effect was significantly better with greater injection pressure and injection time.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1773_1774
• /
• 2009

본 연구에서는 단독주택 지역에 대한 수도검침의 효율성과 경제성을 확보하기 위하여 디지털 수도미터 및 옥외검침시스템을 개발 하였다. 개발품에 대한 다양한 현장 적용을 통하여 시스템의 신뢰성 및 정확성을 확보하여 안정적인 시스템 확대적용의 가능성을 검증하고자 한다. 이러한 현장 적용시험의 결과를 바탕으로 디지털 수도미터의 국가 형식 승인을 획득을 추진하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.367-370
• /
• 2005

In this study, air meter method and capacitance measurement method to apply economically at quality control of ready-mixed concrete among various unit water content measurement technique was selected. Then, it was evaluated estimating performance of unit water content according to the change of water-binder ratio and unit water content. Also, it was examined influence about error occurrence of unit water content by change of properties of used materials. Finally, based on this study, it was proposed fundamental data to utilize measurement technique of unit water content to quality control. of ready-mixed concrete in construction field.

• Journal of Environmental Science International
• /
• v.7 no.3
• /
• pp.311-320
• /
• 1998

The volume transport and turnover time of the Deukryang Bay. located at the southern area of Korea, were calculated based on the current meter(RCM-7,ACM 16M) data observed at the three gateways of the tegrating observed data and then averaging on time. dangdo and Kogumdo. The total water volume transports through three entrances of the bay in May and October were $3.9{\times}10-2Sv, 3.4{\times}10^{-2}Sv(1Sv=10^6m^3s^{-1}$) and turnover time were 0.97day, 1.12day, respectively. Semidiurnal tides were predominant (70~85%). The water volume transports by residual currents were 2~4% of total water volume transports . The average fraction of fresh water calculated by tidal prism method using salinity difference between inflow current and outflow current through three entrances In Deukryang Bay was about 0.06% of total volume and the flushing time of fresh water was estimated as 0.97day.

• Journal of Korea Water Resources Association
• /
• v.30 no.6
• /
• pp.671-678
• /
• 1997

Water surface velocity meters with microwave were applied to stream discharge measurements and its practical aspects were evaluted. The rating of the surface velocity meters was performed through a carriage and a water tank for the ship model test. It gave5.5% or less errors of average measured velocities under the vertical tilt ang1e of 20$^{\circ}$, 35$^{\circ}$, or 45$^{\circ}$ . A surface velocity meter was used to measure flood velocities at Yoju bridge from 8:00 a.m. to 10:00 a.m. on August 26, 1995. The results showed that surface velocities ranged from 2 to 4 m/s. With the measured surface velocities multiplied by 0.85, the discharge was computed as 10,500 m$^3$/s. It differed $\pm$2% or less from the value of a stage-discharge curve and that of an unsteady flow simulation. Although the measured data are used sparsely per 40 or 60 meters, the computed discharges do not give large variation. Stream discharge measurements were also performed under the normal condition without floods. With the known values of Taechong Dam releases. the depth averaging factors of velocity were calculated by 0.83~0.87. Although there are errors from wind action and inherent ones in the velocity meters, the research showed that surface velocity meters could be an simple and practical alternative for flood discharge measurements.

• Journal of Bio-Environment Control
• /
• v.21 no.4
• /
• pp.354-361
• /
• 2012

This study was conducted to evaluate on the freezing tolerance of introduced blueberry cultivars in Korea and to investigate availability of portable timber moisture meter for simple and rapid diagnosis of blueberry-shoot damage by freezing during wintering. Frost tolerance of blueberry cultivars showed big difference that rates of blueberry-shoot death were widely distributed from about 0% to 100% after wintering. Optical density in TTC reduction of blueberry twig treated low temperature was low in order of $-40^{\circ}C$ < $-21^{\circ}C$ < $4^{\circ}C$. Hardiness evaluation of visible injury in the cross-sectional surface color did not agree with that of rates of blueberry-shoot death during wintering. Lowest water content of blueberry stem measured by timber moisture tester during wintering was about 15%. During wintering, water contents of blueberry stems were higher at lower part of tree, but were low at end part of stems, and then when the blueberry grew again for spring, the water content gradually increased to 20~40%. Water content of blueberry stem with freezing injury during wintering decreased to under 5% by desiccation. Therefore it is assummed that the moisture content of blueberry stem injured by freezing during wintering was about under 14%, and it is expected that portable timber moisture meter could be available for rapid diagnosis of blueberry freezing injury in field.